History and current status of the National Notifiable Diseases Surveillance System.

The National Notifiable Diseases Surveillance System (NNDSS) has origins dating more than a century ago and continues to serve today as a timely source of national data. Both the history and the current status of the NNDSS illustrate the collaborative effort required among persons at all levels of the medical and public health systems. The evolution of the list of conditions considered nationally notifiable demonstrates the responsiveness of the system to changing priorities. The NNDSS has also evolved with the development of technology; it currently uses computers for the collection of data rather than letters or telegrams. These fundamental factors--partnerships, shifting priorities, and rapidly changing technology--will continue to characterize and to influence the practice of public health surveillance as it evolves during the 21st century.